glGetError
[New
- Windows 95, OEM Service Release 2]
The glGetError
function returns error information.
GLenum glGetError(
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void |
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); |
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Remarks
The glGetError
function returns the value of the error flag. Each detectable error is assigned
a numeric code and symbolic name. When an error occurs, the error flag is set
to the appropriate error code value. No other errors are recorded until glGetError
is called, the error code is returned, and the flag is reset to GL_NO_ERROR. If
a call to glGetError returns GL_NO_ERROR, there has been no detectable
error since the last call to glGetError, or since OpenGL was
initialized.
To allow for
distributed implementations, there may be several error flags. If any single
error flag has recorded an error, the value of that flag is returned and that
flag is reset to GL_NO_ERROR when glGetError is called. If more than one
flag has recorded an error, glGetError returns and clears an arbitrary
error flag value. If all error flags are to be reset, you should always call glGetError
in a loop until it returns GL_NO_ERROR.
Initially,
all error flags are set to GL_NO_ERROR.
The following
are the currently defined errors:
GL_NO_ERROR
No error has
been recorded. The value of this symbolic constant is guaranteed to be zero.
GL_INVALID_ENUM
An
unacceptable value is specified for an enumerated argument. The offending
function is ignored, having no side effect other than to set the error flag.
GL_INVALID_VALUE
A numeric
argument is out of range. The offending function is ignored, having no side
effect other than to set the error flag.
GL_INVALID_OPERATION
The specified
operation is not allowed in the current state. The offending function is
ignored, having no side effect other than to set the error flag.
GL_STACK_OVERFLOW
This function
would cause a stack overflow. The offending function is ignored, having no side
effect other than to set the error flag.
GL_STACK_UNDERFLOW
This function
would cause a stack underflow. The offending function is ignored, having no side
effect other than to set the error flag.
GL_OUT_OF_MEMORY
There is not
enough memory left to execute the function. The state of OpenGL is undefined,
except for the state of the error flags, after this error is recorded.
When an error
flag is set, results of an OpenGL operation are undefined only if GL_OUT_OF_MEMORY
has occurred. In all other cases, the function generating the error is ignored
and has no effect on the OpenGL state or frame buffer contents.
Error Codes
The following
are the error codes generated and their conditions.
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Error
Code |
Condition |
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GL_INVALID_OPERATION
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glGetError was called between a call to glBegin and the
corresponding call to glEnd. |
See Also
glBegin, glEnd